While in the grand scheme of things, five seconds isn’t all that long, it’s longer than you may think. One common question received by the Vac-Con Service Department is “Why do the engine lights keep coming on in the chassis?” You may be surprised to learn that nearly 60 percent of all engine light problems result from an incomplete ECM system check. 

Your next thought is most likely, “What is an ECM system check? And why does this happen?” The ECM (Engine Control Module) in the engine has to identify all of the sensors in the chassis; it has to look for each address and then recognize it and ensure that it is functioning properly. This process takes about five seconds. These days, we are so accustomed to immediacy that waiting for five measly seconds seems like an eternity. You may hear some clicks and clacks but this is just the process going through its motions; even the gauges in the instrument panel undergo a sweep.

If we jump in the cab and start the truck immediately, the ECM is unable to complete its check and not only will the check engine light stay on, but often times this will result in a fault code being sent to the engine inhibiting the engine from running at full power. So if your truck was running fine yesterday but seems sluggish today, you need to be sure to wait the five seconds and let this sweep complete. 

There, simple as that. Tick tock.